| About 50 standard strains in Bacillus genus were introduced from Sweden CCUG and Germany DSMZ, after activating, the standard strains were preserved using freezing dry method, of which the data were tested and corrected through morphological characteristics, physical and biological characteristics, fatty acid and 16S rRNA sequence. The sample preservation of Bacillus strain was conducted by freeze dry method with the quantities of 109 Bacillus spores in the storege of common condictions.Bacillus strains were tested based on 14 biochemistry factors, among which, the numerical cluster analysis showed that the similarity coefficient at 65%, Bacillus strains were divided into 6 groups. In most of Bacillus strains, the biochemical characteristics of catalase reaction, oxidase reaction, glucose fermentation, amylolysis reaction were positive, but some of them such as benzpyrole reaction, citric acid reaction, hydrothion reaction were negative.The phylogeny cluster analysis with 16s rRNA showed that Bacillus strains were divided into 5 groups. Based on the comparation of 16s rRNA sequence homology, in group I, the homology of Bacillus cereus, Bacillus mycoides, Bacillus thuringiensis was more than 98%. That of Bacillus simplex, Bacillus psychrosaccharolyticus, Bacillus flexus and Bacillus megaterium was up to 100%. In group II the homology of Bacillus subtilis and Bacillus cellμlosilyticus was up to 100%. In groupⅣthe homology of Bacillus farraginis, Bacillus fordii, Bacillus fortis was more than 97%. GroupⅤ, the homology of Bacillus fusiformis, Bacillus sphaericus was up to 100%, that of Bacillus pasteurii and Bacillus psychrophilus was more than 97%. In groupⅥthe homology of agaadhaerens, Bacillus clarkii was up to 100%, that of Bacillus centrosporu and Bacillus thiaminolyticus was more than 98%.All Bacillus strains had 15:0 ISO fatty acid biomarkers (PLFAs), in addition, 14:0, 15:0 ANTEISO, 17:0 ANTEISO, 17:0 ISO also existed in most of Bacillus strains. Meanwhile, Bacillus strains tested were divided into 5 groups by cluster analysis of PLFAs. Comparing to 16s rRNA cluster analysis, it was found that the both results had the similarity.The antagonistic action of Bacillus strain to Escherichia coli, Ralstonia solanacearum and Fusarium oxysporum was studied in the paper. The result was that 11 strains had antagonistic action to Ralstonia solanacearum, the strong inhibiting strains were Bacillus atrophaeus, Bacillus mycoides, Bacillus psychrosaccharolyticus, Bacillus smithii, Bacillus sphaericus, Paenibacillus amylolyticus, Bacillus endophyticus, Paenibacillus alvei . About 11 strains had antagonistic action to Escherichia coli, the strong inhibiting strains were Bacillus atrophaeus, Bacillus subtilis, Bacillus huringiensis, Paenibacillus alvei. Sixteen strains had antagonistic action to Fusarium oxysporum, inhibition ratio of Bacillus laevolacticus against Fusarium oxysporum was about 73.3%.
|
PDF Full Text Request